chore: Add SPDX lincense headers

Author: alerque

after/ftplugin/markdown.vim

@@ -1,3 +1,7 @@
+" SPDX-FileCopyrightText: © 2022 Caleb Maclennan <caleb@alerque.com>
+" SPDX-FileCopyrightText: © 2009 Benjamin D. Williams <benw@plasticboy.com>
+" SPDX-License-Identifier: MIT
+
 " folding for Markdown headers, both styles (atx- and setex-)
 " http://daringfireball.net/projects/markdown/syntax#header
 "

doc/vim-markdown.txt

@@ -651,7 +651,8 @@ License ~
 
 The MIT License (MIT)
 
-Copyright (c) 2012 Benjamin D. Williams
+Copyright (c) 2022 Caleb Maclennan
+Copyright (c) 2009 Benjamin D. Williams
 
 Permission is hereby granted, free of charge, to any person obtaining a copy of
 this software and associated documentation files (the "Software"), to deal in

ftdetect/markdown.vim

@@ -1,3 +1,7 @@
+" SPDX-FileCopyrightText: © 2022 Caleb Maclennan <caleb@alerque.com>
+" SPDX-FileCopyrightText: © 2009 Benjamin D. Williams <benw@plasticboy.com>
+" SPDX-License-Identifier: MIT
+
 if !has('patch-7.4.480')
     " Before this patch, vim used modula2 for .md.
     autocmd! filetypedetect BufRead,BufNewFile *.md

ftplugin/markdown.vim

@@ -1,3 +1,7 @@
+" SPDX-FileCopyrightText: © 2022 Caleb Maclennan <caleb@alerque.com>
+" SPDX-FileCopyrightText: © 2009 Benjamin D. Williams <benw@plasticboy.com>
+" SPDX-License-Identifier: MIT
+
 "TODO print messages when on visual mode. I only see VISUAL, not the messages.
 
 " Function interface philosophy:

indent/markdown.vim

@@ -1,3 +1,7 @@
+" SPDX-FileCopyrightText: © 2022 Caleb Maclennan <caleb@alerque.com>
+" SPDX-FileCopyrightText: © 2009 Benjamin D. Williams <benw@plasticboy.com>
+" SPDX-License-Identifier: MIT
+
 if exists('b:did_indent') | finish | endif
 let b:did_indent = 1
 

syntax/markdown.vim

@@ -1,3 +1,7 @@
+" SPDX-FileCopyrightText: © 2022 Caleb Maclennan <caleb@alerque.com>
+" SPDX-FileCopyrightText: © 2009 Benjamin D. Williams <benw@plasticboy.com>
+" SPDX-License-Identifier: MIT
+
 " Read the HTML syntax to start with
 if v:version < 600
   source <sfile>:p:h/html.vim